Six cats have died from what Oldham County Animal Control believes is antifreeze poisoning, and director Barbara Rosenman said she suspects there may be more casualties.

Two cats were found dead at the scene on Thursday, one died after capture, and three more were euthanized after showing signs of poisoning and suffering.

The apartment complex is home to a managed cat colony, Rosenman said, which maintains about a 20-cat population.

The colony is one of several in the county and is a way to reduce strain on the animal shelter without having to euthanize animals.

Through a trap, neuter and release program, more than 40 cats have been picked up from the complex, sterilized, vaccinated and returned to what is, in fact, their home — even if a human owner no longer lives there.

Cats often are left behind when apartment residents move, she said, and that is how the colonies form.

Through the TNR program, the cats help manage the rodent population often exacerbated by large apartment dumpsters.

“I’d rather have cats than rats,” Rosenman said.

Cats released by the OCAC into the colony also have blunted ears so they can be identified in the future. All the poisoned cats had that marker, Rosenman said.

When OCAC was called to the scene last week, they found a “pan with tuna casserole” set out for the cats.

“It was shiny and shimmery with antifreeze,” Rosenman said.

La Grange Police are assisting with the investigation, including sending off the remaining food for testing.

They are also working with state labs to process any potential fingerprints found on the pan, according to Chief Kevin Collett.

Two of the deceased cats have been sent for autopsy by a veterinarian to confirm cause of death, Rosenman said.

Collett said several officers are working on the case in conjunction with the OCAC, which remains the lead investigating agency.

Right now both agencies are waiting for test results, although Rosenman said it could take time since human cases take priority.

But, both Rosenman and Collett confirmed there are several people of interest, and officials are conducting interviews.

“We take it seriously and we will prosecute,” Rosenman said. “It is against state and county law.”

A $500 reward is being offered by the Humane Society of Oldham County for information leading to the conviction of the poisoner, according to Lisanne Mikan, HSOC vice president.

The poisoning “could’ve had far-reaching implications,” Rosenman said, had if it lured over someone’s pet.

Or, even worse: “What if a 6-year-old came over and ate it?” she asked.